Highly fluorescent carbon dots as an efficient nanoprobe for detection of clomifene citrate.

Highly fluorescent carbon dots (CDs) were synthesized through facile hydrothermal carbonization and ethylenediamine passivation of an easily available prawn shell precursor. The as-prepared CDs exhibit high water solubility, wavelength-tunable fluorescence with quantum yield up to 68.9%, high photostability and resistance against biomolecules, thus enabling the application as viable fluorescent nanoprobes for detection of guest quenchers. The fluorescence of the CDs can be effectively quenched by clomifene citrate (CC, a common drug for infertility) through static quenching, and therefore can serve as a simple and efficient fluorescent nanoprobe for determination of CC with wide linear range (0.25-10 µg mL-1) and low detection limit (0.2 µg mL-1). The CDs also showed low cytotoxicity, which enables the safe and accurate fluorescent detection of spiked CC in human serum, demonstrating their potential as a credible fluorescent CC nanoprobe in clinical examination.

[Effect of ropivacaine on proliferation and migration of rat bone marrow mesenchymal stem cells].

OBJECTIVE: To observe the influence of ropivacaine on the proliferation and migration of rat bone marrow mesenchymal stem cells (BMSCs) and provide basis for the clinical application of BMSCs. METHODS: Rat BMSCs were isolated and cultured by adherence method. Surface markers of BMSCs were examined by flow cytometry. Multipotent differentiation of BMSCs was detected by induced adipogenesis, osteogenesis and muscular differentiation. Proliferation of BMSCs was examined by CCK-8 and Brdu incorporation after ropivacaine treatment at different concentrations. Migration of BMSCs was tested by cell scratch assay and Millicell experiment. RESULTS: Cultured cells had representative appearance and surface markers of BMSC, and they had potential multiple differentiation. Ropivacaine treatment at 50 and 100 µmol/L significantly reduced the proliferation rate of BMSCs and Brdu incorporation rate. There was significant difference compared with the control group (P<0.05). Cellular scratch assay and migration experiment indicated that ropivacaine significantly reduced the migration of BMSCs. There was significant difference compared with the control group (P<0.05). All these mentioned effects of ropivacaine on BMSCs were dose-dependent. There was significant difference between groups (P<0.05). CONCLUSION: Ropivacaine can significantly reduce the proliferation and migration of rat BMSCs, suggesting that the influence of local anesthetics on BMSCs has to be taken into account when BMSCs are used in clinical practice.

Soluble expression in Escherichia coli of active human cyclic nucleotide phosphodiesterase isoform 4B2 in fusion with maltose-binding protein.

Recombinant expression in Escherichia coli of human cyclic nucleotide phosphodiesterase 4B2 (hPDE4B2) fused to maltose-binding-protein (MBP-hPDE4B2) was investigated. hPDE4B2 DNA amplified via nested RT-PCR with total RNAs from U937 cells was ligated with pMAL-p2x. After induction at 18 degrees C for 16 h, soluble MBP-hPDE4B2 was produced in E. coli. MBP-hPDE4B2 after amylose-resin chromatography showed 35% homogeneity, and its Michaelis-Menten constant was 10+/-2 microM (n=3). Rolipram had a dissociation constant of 9+/-2 nM (n=2), and zinc ion was a potent inhibitor. Hence, MBP-hPDE4B2 was expressed in E. coli as a soluble active protein.